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Notch信号通路是肿瘤形成过程中一种重要的信号通路,其中心分子为Notch受体.Notch受体为细胞膜上的单次跨膜蛋白,介导细胞间信号转导,哺乳动物细胞内包括Notch1、Notch2、Notch3和Notch4的4个成员.Notch家族4个蛋白质在结构和功能上存在差异.前期研究显示,Notch1信号通路与转录因子YY1(YING-YANG 1)、表皮生长因子受体(EGFR)间存在调控作用.本研究在人胰腺癌细胞HPAC中,采用RNA干扰技术,分别降低细胞中Notch家族4个蛋白质的表达,检测YY1和EGFR在m RNA和蛋白质水平上的表达;并构建相应的激活形式的Notch受体——Notch胞内结构域(Notch intracellular domain,NICD)真核表达质粒,在HPAC细胞中分别过表达4种NICD,检测其对YY1和EGFR表达水平的影响.结果显示,降低细胞中Notch1或Notch3的表达,均使HPAC细胞中EGFR m RNA和蛋白质水平升高(P<0.05),而降低Notch2和Notch4后,EGFR m RNA和蛋白质水平没有改变(P>0.05).分别降低4个Notch的表达,对YY1的蛋白质和m RNA表达水平均没有改变(P>0.05).在HPAC细胞中过表达N1ICD和N3ICD后,YY1和EGFR的蛋白质水平降低(P<0.05),而过表达N2ICD和N4ICD后,YY1和EGFR蛋白质水平没有改变(P>0.05).分别过表达4种NICD均没有改变YY1和EGFR的m RNA表达水平(P>0.05).初步得出结论是,在HPAC细胞中,Notch信号通路经Notch1和Notch3影响EGFR的表达.Notch1和Notch3对EGFR的表达可能具有负调控作用.在Notch1和Notch3过度激活时,这种调控作用通过YY1介导.本文可为深入研究Notch信号通路对胰腺癌发生发展的作用机制提供有意义的参考.
Notch signaling pathway is an important signal pathway in tumorigenesis, its central molecule is Notch receptor.Notch receptor is a single transmembrane protein on the cell membrane, which mediates cell-cell signal transduction, and mammalian cells include Notch1 , Notch2, Notch3 and Notch4 .Notch family of four proteins in the structure and function differences.Previous studies have shown that Notch1 signaling pathway and transcription factors YY1 (YING-YANG 1), epidermal growth factor receptor (EGFR) In this study, RNA interference technology was used to reduce the expression of Notch family of four proteins in human pancreatic cancer cell line HPAC to detect the expression of YY1 and EGFR at m RNA and protein levels, and to construct the corresponding The eukaryotic expression plasmid of Notch receptor Notch intracellular domain (NICD) was used to overexpress four NICDs in HPAC cells to detect the effect of NICD on the expression of YY1 and EGFR.The results showed that, Decreasing the expression of Notch1 or Notch3 in cells both increased the mRNA and protein levels of EGFR m RNA and protein in HPAC cells (P <0.05), while decreased the mRNA and protein levels of EGFR m RNA and protein in Notch2 and Notch4 cells (P> 0.05). (P> 0.05) .Not down-regulated the expression of Notch, but had no effect on the expression of YY1 protein and m RNA (P> 0.05) .The protein level of YY1 and EGFR decreased in HPAC cells after N1ICD and N3ICD overexpression The overexpression of N2ICD and N4ICD did not change the protein levels of YY1 and EGFR (P> 0.05) .The overexpression of 4 NICD did not change the mRNA expression level of YY1 and EGFR (P> 0.05) In HPAC cells, Notch signaling pathway affects EGFR expression through Notch1 and Notch3, and Notch1 and Notch3 may have a negative regulatory effect on EGFR expression.This regulation may be mediated through YY1 when Notch1 and Notch3 are over-activated. In-depth study of Notch signaling pathway for the development of pancreatic cancer mechanism of action provide a meaningful reference.